The Animal Core will provide the following services to individual projects: (1) breed the appropriate numbers of mice including the TCR OVA Tg (DO. 11.10; DO 11), IL-16 and IL-9 airway epithelial cell Tg (CC10 promoter), and cytokine, receptor, and mediator deficient lines (IL-16 -/-, STAT1 -/-, BALB/c-1pr, BALB/c-gld, LPB -/-, CD14 -/-, Toll-like receptor 2 (TLR2) -/- and Toll-like receptor 4 (TLR4) -/-); (2) make chimeric mice by reconstituting irradiated recipients with donor bone marrow stem cells; (3) sensitize and challenge the experimental animals involved in airway hypersensitivity studies by intraperitoneal and aerosol delivery of antigen; (4) collect tissue specimens including serum samples, fluid and cells obtained by BAL and lung biopsies; store, and distribute experimental samples; (5) assess airway function by determining bronchial resistance to inflation to increasing doses of methacholine; and (6) provide biostatistical support for all animal studies. The intent of the Animal Core is to efficiently generate sufficient numbers of experimental mice accurately phenotyped for Projects 1, 2 and 3 and to perform and/or monitor the various technical manipulations of the airway hypersensitivity and chimeric animal models. The Animal Core will thereby provide easily accessible and readily reproducible animal models that will facilitate the further exploration of the role of IL-16, FasL, and microbial products in the regulation and/or exacerbation of immune hypersensitivity reactions. Further, it will eliminate duplication of effort and animals by creating a central archive, storage and distribution system for all animals studied.